Cyclooxygenase, the enzyme that catalyzes the production of prostaglandins from arachidonic acid, has long been thought to play a role in exacerbating injury due to cerebral ischemia via its vascular and inflammatory effects. Recently it has been found that the inducible isoform of the enzyme, cyclooxygenase 2 (COX2), is expressed in high levels within neurons. We hypothesize that COX2 activity within the neuron itself promotes cell death after hypoxia/ischemia. The proposed experiments are designed to test whether COX2 activity exacerbates anoxic injury by oxidative stress, production of prostaglandins including the cyclopentenone prostaglandins, or both. The following specific aims are proposed: 1. Test whether COX2 activity exacerbates anoxic injury through production of oxidative stress via peroxidase activity. 2. Test whether COX2 activity exacerbates anoxic injury through production of prostaglandins via cyclooxygenase activity. 3. Test whether 15-deoxy-delta(12,14) -PGJ2 or other prostaglandins activate PPARgamma receptor binding and exacerbate anoxic neuronal death via activation of the PPARgamma receptor. COX2 activity has been implicated in the pathogenesis of stroke and neurodegenerative diseases, including Atzheimer's disease and amyotrophic lateral sclerosis. The current studies will address the mechanisms by which COX2 activity can directly injure neurons and thus could lead to new therapeutic strategies for stroke and neurodegenerative diseases.